In one case, a thief “opened the wall of a dispensary with an ax and attacked the store’s safe with a circular saw,” the report by Tony Dokoupil and Bill Briggs says.

It says thieves are seeking money and marijuana from pot shops and dispensaries. One team of crooks hit at least eight dispensaries over a six-week period.

Sales of recreational marijuana in Colorado began Jan. 1, and sales of pot for medical purposes has been under way here for several years.

The report notes that because marijuana sales remain illegal under federal law, most pot businesses lack full banking service and deal in cash, making them vulnerable and attractive targets for thieves.

NBC cites data showing that among 325 marijuana businesses in Denver, there have been 317 burglaries and seven robberies over the last two years, and that thefts are happening at a higher rate than a few years ago.